1. Technical Field
The present invention relates to an access control device and an electronic device, and more particularly, to an access control device which controls an access right with respect to a plurality of electronic devices present in a network for each combination of electronic devices, and an electronic device which achieves a desired service in association with an application stored in another electronic device via a network, in accordance with a control of the access right by the access control device.
2. Background Art
Conventional electronic devices, such as a digital TV, a mobile telephone, and the like, are increasingly having a function of downloading a program described in Java® language or the like and executing the downloaded program. For example, in the field of mobile telephones, NTT DoCoMo provides a service called “i-appli”. In the service, a mobile telephone terminal downloads a Java® program from an application distribution server on the Internet, and executes the program on the terminal. In Europe, a specification called “DVB-MHP (Digital Video Broadcasting-Multimedia Home Platform)” has been established, and a service was already started in conformity with the specification. In digital broadcasting based on the DVB-MHP standards, a digital TV receives and executes a Java® program multiplexed with a broadcast wave.
In such a program distribution service, a number of security functions are incorporated so as to prevent unauthorized access of an application to an electronic device. By using the security functions, conventional electronic devices prevent unauthorized access from an application created by, for example, a malicious creator. Specifically, conventional electronic devices are provided with, for example, a function of confirming authentication information given to an application to confirm the identity of a creator of the application, a function of controlling API (Application Programming Interface) for accessing a computer resource available on an electronic device, depending on the presence or absence of authentication information, or the like.
Patent Document 1 discloses a conventional electronic device having a function of preventing unauthorized access. FIG. 19 is a block diagram illustrating an exemplary configuration of the conventional electronic device. In FIG. 19, the conventional electronic device 900 comprises computer resources 901a to 901c, an application executing section 902, and an access permission control section 903. The computer resources 901a to 901c are resources which are used by the electronic device 900 so as to achieve a predetermined function. Specifically, the computer resources 901a to 901c are a memory resource, a resource for achieving connection with respect to an external device, and the like. The application executing section 902 downloads an application program 902a via a network from an application server 910. When the application program 902a is proved not to be an unauthorized program by a third party or the like, authentication information 902b is attached to the application program 902a. 
When the authentication information 902b is attached to the application program 902a, the access permission control section 903 permits access of the application program 902a to all the computer resources 901a to 901c. On the other hand, when the authentication information 902b is not attached to the application program 902a, the access permission control section 903 prohibits access of the application program 902a to all the computer resources 901a to 901c. Thus, the conventional electronic device 900 prevents access of unauthorized programs to the computer resources 901a to 901b. 
In recent applications, there are not only an application which achieves a predetermined service using a single electronic device, but also an application which achieves a predetermined service in association with a plurality of electronic devices via a network. Examples of an electronic device which executes such an application include a mobile telephone which performs timer recording with respect to a video recorder device, a personal computer which shares image data, and the like. When executing such an application, the conventional electronic device 900 controls access of unauthorized applications to a computer resource for network connection, thereby controlling connection to all networks (i.e., all devices).
Patent Document 1: Japanese Patent Laid-Open Publication No. 10-320287